nxv200 Listen Impressions and Improvements

[ackcheng]

any comments on the Mcaps on nxv200, Anthony?

[Aussieamps]

Hi Ackcheng

There is a lot going on at the moment, However I will see if I can get the
caps fitted this weekend.

I do have to get these caps back to Oval56 after all.
Thanks again mate for the loan of them...

[56oval]

I do have to get these caps back to Oval56 after all.
Thanks again mate for the loan of them...

Hello Anthony

Take your time I don't need them for awhile they came out of the spare dac .
Hows the chassis coming along .
Cheers

[Aussieamps]

Hello Anthony

Take your time I don't need them for awhile they came out of the spare dac .
Hows the chassis coming along .
Cheers

Hi Mal

I spend the best part of last friday with Lucas at his office, going over the
design of the chassis. Its looking very good so far.
It will be made in such a way so the nxv200, nxv300 and nxv500 modules
will drop straight into it.
And it will have different power supply boards made for each module pair.
The chassis will be low profile 75mm high using Conrad's MF35-75 heat sinks. all with loudspeaker and amplifier protection on board.

It's going to look great!

[Hi Five]

Hi all
Anthony made the nxv200 for me , the improvement over the avr300 is mind blowing .More detail and base control in movies [war of the wolds] .

[Aussieamps]

Hi Everyone

Here is some more testimonials raving about the nxV200 Amplifier.
At this link below.
http://www.aussieamplifiers.com/nxv200.htm

[56oval]

Hello Anthony.

I had a look at your nxv500 module the other day at Lucas's ,very nice .

Cheers

[datafone]

Hi all
Anthony made the nxv200 for me , the improvement over the avr300 is mind blowing .More detail and base control in movies [war of the wolds] .

So what would one of these cost complete?

[Aussieamps]

So what would one of these cost complete?

Hi Datafone

A complete stereo nxv200 amplifier as shown on my web site is $1950.00 inc GST and delivery within Australia...

If you have any other questions please ask.

[datafone]

Thanks Anthony, that's all the info I need at the moment, just looking at different options

Cheers
Ian

[Aussieamps]

Hi Everyone

A few more testimonials and photos have now been posted onto the web site Gallery
Check them out!
http://www.aussieamplifiers.com/gallery.htm

[rabbitz]

Over the last few years I have tried a fair portion of the more popular DIY power amplifier designs on offer. The ones I admit to are from Aspen (AKSA 55, 55N, 55N+, Lifeforce 55), AudioSector (LM3875, LM4780), Aussie Amps (NX150), ESP (P3A, P101), SKA (GB150). I’m not going to compare the NXV200 to any of these amplifiers as they are well documented elsewhere.

I accidentally came upon the NXV200 after talking to Anthony on another matter and the entry price for a fully built amplifier module was very attractive. I do not run at super high SPLs but I do require the ability to run low impedance speakers (some of my designs dip less than 4R), so the amplifier I built uses 42V rails giving 80W into 8R and 130W into 4R which is more than enough for my requirements. The power supply differs to Anthony’s and consists of 6 - 4700uF Nichicon (KG) Gold Tunes in a "C" type arrangement with other little tricks. This was fed via a Harbuch 300VA 30-0-30 transformer and a standard 35A 400V bridge rectifier. Several input caps were tried starting with a 22uF BlackGate NX on the PCB, a 2.2uF Mundorf M-Cap at the RCA and 3.3uF Mundorf M-Cap Supreme at the RCA. In the end the Mundorfs might have had a slight edge in the higher registers but the BlackGate NX seemed to have tighter control, so is going to be used in the final amp.

The test system used a Cambridge 840C and a modded Sony CDP-990 as sources, a DIY Burson Buffer based pre and a NAD 106 pre amp, speakers were my designs with one a pseudo 3-way (Scan Speak S2905-970000, Scan Speak 18W8531 (coated), Vifa M22WR09-08) and the other a 2-way (Vifa XG18WH00-08, Peerless 810921). In other words, very capable and resolving.

Assembly of the module is a snap and the instructions cover most things that an experienced builder needs. If you have any doubts, Anthony is only an email away and does provide great support.

At startup and shutdown, there are no pops, thumps, farts, driver movement so all is well behaved and you don’t have to cringe when you fire up or shutdown.

The first thing that stands out is the amount of control and smoothness on offer. I have never heard an amplifier that controls the woofer so well and when the note finishes it stops on a dime. There’s no overhang at all and that really contributes to the fine bass tonal quality. The drive, dynamic capabilities, timing and pace are right on the money and allows the rhythm of the music to flow. A good example is Bélla Fleck’s "Flight of the Cosmic Hippo" which has some of the most awkward low bass known to man. The NXV200 controlled it extremely well allowing the timbre and strange quality of the bass to come through unimpeded which is very impressive as not many amps are faithful to it.

This amplifier majors on smoothness and there is no bleeding ears factor here. I’m a large fan of the great late Eva Cassidy and since a lot of the recordings are raw, lesser amplifiers can shred your ears when she hits those higher notes, but not the NXV200. It remained composed, the voice flowed and the presentation was completely musical allowing a good insight into this great performer’s music and voice. I’ve heard so many commercial amplifiers out there that get this so wrong and in the end, the user hardly uses them.

This smoothness does have a small downside and all amplifier designs are compromises. The top end can be a little polite at times and some of the detail in the background does not completely have it’s own space. It’s still there but in the mix. This by the way is not a bad thing and will only upset the detail freaks out there but if you value musicality, then it’s not an issue and I found it mattered nought. If I want massive detail, I have other amps for that but they sometimes can become fatiguing, especially with a lot of the later CDs.... you takes your choice. The overall presentation is very refined indeed you can’t seem to do critical listening as it just draws you into the music with it’s presentation. There is no fatigue factor at all and the first listening session was 4 hours and I just grabbed disc after disc with the foot tapping and a grin.

It’s important to get the combination of components right and that’s the hardest thing to do in this game. The NXV200 will be used in my office with some nearfield monitors so it’s smoothness and control is very important. An edgy sound in this location is not desirable. I would suggest that the NXV200 be partnered with equipment that are neutral or on the bright side of neutral as that would provide the best balance. If you have a system that is edgy and making your ears bleed, then this could be the ticket to happier listening. I would not put it in a dull system and that would degrade the sonics on offer and kill the overall presentation.

This next comment is not meant to be degrading but is a compliment. It’s a bit like the NAD philosophy where you get a nice full bass, open mids, refined presentation, paint a nice image and don’t let the top end offend. Not a bad place to be and a fine design choice which places musical enjoyment foremost.

All in all, a fine amplifier indeed and congratulations go to Anthony. Anthony might eventually comment on the design choices made as amplifier design is about picking the right compromises and of course, the expected market.

I've attached some pics of the inside of the amp, the case in situ and the test system.

[Drizt]

Very impressive mate, lovely system.

[Hi Five]

Hi all
UPDATE Added 3.9uF Mundorf M-Cap Supreme at the RCA `s made big difference .Larger sound stage,smoother top end and the instruments are so clear .Had to stop my self from having a look in side the speakers for the band

P.S. Have now done 6 hours burn in only 294 hours to go .This has to be the best/cheapest $80 sent so far on my HI-FI.

[56oval]

Hi all
UPDATE Added 3.9uF Mundorf M-Cap Supreme at the RCA `s made big difference .Larger sound stage,smoother top end and the instruments are so clear .Had to stop my self from having a look in side the speakers for the band

Try the silver/oils .

Cheers

[Aussieamps]

Hi Everyone

Rabbitz thank you so much for the effort you went to do the review.
It is now posted along with the photos on the web site Gallery.

Hi Five
Awesome mate great to hear your nxv200 is sounding even better.
Which reminds me 56Oval I must get around to trying those silver -oils you sent me.

Today I quickly put together an Anthology of Aussie Amplifiers.
You might find it quite amusing and I hope interesting.
Its a photographic history to music of my journey so far in the DIY audio world.
Its show a lot of what I have done since 1994, However there is still a lot I was not able to fit in.
Perhaps part two might be in order...

It has been posted on www.youtube.com and on my web site front page and in the Links page.
Here is the link to it. http://www.youtube.com/watch?v=Gp4_6qjdG-8

[AKSA]

Rabbitz,

Terrific review, beautifully expressed, and hats off to Anthony for what is clearly a wonderful, well priced module amplifier!

Hugh

[rabbitz]

Thanks for your kind words Hugh.

I must add to my review that my NXV200 is running rails below the recommended minimum power supply and slightly lower capacitance so I may not be achieving the full potential on offer. I was going to try a higher voltage transformer but was over the maximum recommended, even allowing for losses, due to poor regulation even though the stated voltage was fine.

The amp went into the office today and as predicted was a great match for the nearfield monitors and application.

[AKSA]

Peter,

I think you are right. As a general rule, I've found that as you raise the rail voltage, the stability margin of the amp reduces, and you must revisit the compensation to recover stability into a wide range of loads.

Alternatively, if you lower the rail volts, the stability margin improves, and the sonically toxic compensation regime can be relaxed. This almost always improves sonics. If the compensation is not changed, then the sonics degrade slightly with lower voltage rails.

Cheers,

Hugh

[skood]

Hi Anthony, wondering how the pre-amps coming along;

Also how does the hpa400lspse compare to the nsx150; are they different designs?



Cheers

[rabbitz]

Thanks for the explanation Hugh.... even in language I can understand.

[Aussieamps]

Hi Anthony, wondering how the pre-amps coming along;

Also how does the hpa400lspse compare to the nsx150; are they different designs?



Cheers

First off Rabbitz and Hugh...
Thank you for you kind words Hugh and Thanks for the update Rabbitz.
The other contributing factor to the sound quality would be the thermal changes in the main circuitry. I have spent a lot of time controlling these effects and this module does have a supply rail sweet spot of around +-50 volts DC.

Hi Skood

I am still working on the design and have tested at least one prototype, but there is still a lot more work to be done.

Regarding the LSP400se and nx150 designs.
While they do share some circuit topology, they are worlds apart in actual design. The nx150 uses MOSFETs in all the amplification stages and has an N & P output stage.
The LSP400se has an all N-channel output stage and has Bipolars in the first and second stages of its amplification. It also has built in loudspeaker protection on the main PCB.

[skood]

Hi Anthony,

How do the LSP400se and nxv200 vary sonically?

[Aussieamps]

Hi Anthony,

How do the LSP400se and nxv200 vary sonically?

Hi Skood

The LSP400se is a more warmer sounding amplifier compared to the
nxv200 and the soundstage is a little further back compared to the
nxv200.

Both are great sounding amplifiers all the same...

[Aussieamps]

Hi Everyone

They are more user comments and photos of the nxv200 now posted!
Enjoy

See the web site Gallery....